76 EDWARD PHELPS ALLIS, JR. 



ophthalmic and maxillomandibular branches of the trigeminus 

 issue from the cranium posterior to that process, but two small 

 branches that arise from the intracranial portion of the trigemi- 

 nus ganglion run forward in the cranial cavity and issue from it 

 anterior to the process. One of these two branches is the radix 

 longa. The other separates into two parts, one of which is the 

 ramus ciliaris longa and the other a portio ophthalmici profundi. 

 In a 37-mm. specimen of Cottus aspera, and in a 40-mm. speci- 

 men of Clinocottus, in both of which fishes there is also a process 

 of the parasphenoid that replaces the pedicel of the alisphenoid 

 (Allis, '09), there is a radix profundi which issues from the cra- 

 nium anterior to that process and separates into a radix longa 

 and ramus ciliaris longa, but there is neither portio ophthalmici 

 profundi nor ramus ophthalmicus profundus. In each of these 

 three fishes the profundus ganglion is so completely fused with 

 the trigeminus ganglion that, while its general outlines can be 

 readily determined, it cannot be told whether or not there is 

 any exchange of fibers between the two ganglia. The conditions 

 nevertheless show that where there is both a portio ophthalmici 

 profundi and a process of the parasphenoid that corresponds to 

 the pedicel of the alisphenoid, the portio issues from the cranium 

 anterior to that process. Where there is neither pedicel of the 

 alisphenoid nor corresponding process of the parasphenoid, as 

 in most of the Teleostei, it might be assumed, as already stated, 

 that the portio still existed, but the conditions in the three fishes 

 above described, and those in Scomber (Allis, '03), where there 

 is an independent profundus ganglion, but neither portio pro- 

 fundi nor ramus ophthalmicus profundus, tend to show that 

 both these nerves have wholly disappeared in most of the 

 Teleostei. 



In a 22-mm. embryo of Squalus acanthias, Landacre ('16) finds 

 both a so-called ramus ophthabnicus profundus and a general 

 cutaneous nerve which he considers to be the ramus ophthalmi- 

 cus superficialis trigemini, but the manner of origin of this 

 latter nerve from the trigeminus ganglion is not mcompatible 

 with its being a portio ophthalmici profundi. There is, how- 

 ever, an anterior prolongation of the profundus ganglion that 



